Hi list,

This is my first message to gimp-users, first of all let me thank everyone who contributed to gimp, it's really fantastic. After doing a couple of simple things successfully I have a slightly more complicated problem now and was wondering if anyone had any useful advice.

What I would like to do is take a photo of someone's face and turn it into a cartoon, more precisely into figures that are on ordinary playing cards: Jack, Queen and King. The main feature of these figures are: clear sharp edges and uniform colors between edges. This last thing is the one that I'm not able to create from the photo. I tried all kinds of edge detecting algorithms but the end result was always 'photo-like' in the sense that the colors were not uniform but all kinds of pixels next to each other as is always the case with photos.

Would it be possible to detect sharp edges with uniform colors between them?

What I would like to do is take a photo of someone's face and turn it into a cartoon, more precisely into figures that are on ordinary playing cards: Jack, Queen and King. The main feature of these figures are: clear sharp edges and uniform colors between edges. This last thing is the one that I'm not able to create from the photo. I tried all kinds of edge detecting algorithms but the end result was always 'photo-like' in the sense that the colors were not uniform but all kinds of pixels next to each other as is always the case with photos.

Would it be possible to detect sharp edges with uniform colors between them?

I would suggest keeping the two operations -- outlining and color smoothing -- as separate operations.

If you duplicate your layer and, on the top layer perform your edge detection, followed by a desaturation and color removal, you will be able to erase (or enhance, or de-emphasize) the outline as you desire. On the lower layer, try the Selective Gaussian Blur to smooth out the colored regions.

Using the above technique (crudely), I was able to produce the following transformation:

http://www.imageox.com/image/46549-bush.png

Thanks very much, the example you gave is exactly the kind of thing I would like to do.

I guess I know too little about the terminology here; how do I desaturate the image? And what do you mean by color removal? The top layer should have transparent background, shouldn't it?

I guess what I'm asking is what did you exactly do when you got your example done?

I should add that the Greycstoration Plug-in will also work wonders in cartoonifying an image.

http://www.greyc.ensicaen.fr/~dtschump/greycstoration/index.html

I'll take a look at this as well, thanks.

Daniel

I guess I know too little about the terminology here; how do I desaturate the image?

http://docs.gimp.org/en/gimp-layer-desaturate.html

And what do you mean by color removal? The top layer should have transparent background, shouldn't it?

http://docs.gimp.org/en/plug-in-colortoalpha.html

I guess what I'm asking is what did you exactly do when you got your example done?

Other than edge detection (http://docs.gimp.org/en/plug-in-dog.html), some erasing of "ugly" parts of the top layer, and using the Selective Gaussian Blur
(http://docs.gimp.org/en/plug-in-selective-blur.html), those parts of the GIMP User's Manual pretty well cover it.

Thanks very much for the pointers.

Daniel